Apparatus for scavenging exhaust gases



March 4, 1969 J. L. ELBERSON APPARATUS FOR SCAVENGING EXHAUST GASES Sheet of 2 Filed April 18, 1967 IGNITION IN l/E N TOE.

JOHN L. ELBERSON [5m M W 5) SCAVENGE March 4, 1969 J. L. ELBERSON APPARATUS FOR SCAVENGING EXHAUST GASES Sheet 3 of2 Filed April 18, 1967 IGNITION l 5 3 6 2 4 SCAVENGE //VVNTOK'. JOHN L. ELBERSON United States Patent M 4 Claims ABSTRACT OF THE DISCLOSURE An ignition system for clearing the exhaust of internal combustion engines of unburned gases has means for providing a spark at each cylinder conventionally at the commencement of its power stroke and also for providing an additional spark at each cylinder momentarily during the first half of its exhaust stroke. Such ignition means include dual ignition systems separately timed, dual ignition systems using a common distributor, and a single ignition system having a double contact arm in the distributor, one arm furnishing the power spark and the other the scavenging spark.

Background of the invention This invention relates to ignition systems for internal combustion engines and more particularly to such a system which supplies a momentary sparking at each cylinder during the exhaust stroke as well as at the beginning of the power stroke.

Conventional ignition systems supply only the one momentary sparking at the commencement of the power cycle. Some, such as diesels, supply the equivalent by means of compression. None provide means for burning unburnt gases after the power stroke in the cylinder itself. As a result, the engine emits unconsumed gases which are discharged into the atmosphere or must be further consumed in an after burner.

Summary of the invention This invention contemplates consuming gases left unburnt after the power stroke by causing a spark in the cylinder after the commencement of the exhaust stroke, after the exhaust valve has opened but before the gases have been expelled from the cylinder. Obviously this can be done by dual ignition systems, including a pair of spark plugs for each cylinder. Since the duplication of spark plugs is unnecessary, it is proposed to utilize existing plugs, distributor means and other ignition components as far as practicable.

The principal object of the invention, accordingly, is to provide ignition means for completing the combustion of unburnt but flammable exhaust gases in the engine cylinder before expelling them from the exhaust manifold.

Another important object is to provide ignition systems for the accomplishment of the above stated object utilizing conventional ignition means with as little change as possible.

Other objects and advantages will become apparent from the following description in conjunction with the accompanying drawings.

Brief description of the drawing FIGURE 1 is a diagrammatic and fragmentary view of one cylinder of a multiple cylinder engine and associated ignition system for eight cylinders showing a two armed distributor rotor;

FIGURE 2 is a schematic chart of the firing order of the distributor of FIGURE 1;

FIGURE 3 is a diagrammatic view of a distributor similar to that of FIGURE 1 but for six cylinders;

3,430-,6 l 7 Patented Mar. 4, 1969 FIGURE 4 is a schematic chart of the firing order of the distributor of FIGURE 3;

FIGURE 5 is a diagrammatic view of a distributor similar to that of FIGURE 1 but for four cylinders;

FIGURE 6 is a diagrammatic view of a portion of another ignition system for six cylinders;

FIGURE 7 is a diagrammatic view similar to FIGURE 6 of still another ignition system for six cylinders; and

FIGURE 8 is a schematic chart of the firing order of the system of FIGURE 7.

Description of the preferred embodiment In one cylinder engines it will 'be obvious to those skilled in the art that the magneto providing ignition for the single cylinder may be provided with two sets of breaker points to provide the desired additional sparking at the single plug for the exhaust stroke. In multicylinder engines the problem is more involved and the following embodiments of ignition systems according to the invention are described.

In FIGURE 1, one cylinder of an eight cylinder internal combustion engine is shown at 10, with its piston 11 at, or near the top of its stroke. A single spark plug 12 is located conventionally at the top of the cylinder, recessed in water jacket 13.

Each spark plug of engine 10 is separately connected by an insulated wire 14 to a respective stationary contact 15, in distributor 16, only the Wire to the first cylinder being shown. This connection of plugs to distributor is entirely conventional except that a capacitor 17 is interposed between contact 15 and plug 12 for each wire 14, this interposition not being novel in ignition systems. Capacitor 17 may be carried by the wire, as shown, or by distributor 16 or plug 12.

Centrally of the distributor 16, the distributor shaft 20 carries the usual arm 21, which is insulated from contacts 15, the shaft 20 being synchronized with the cyclical movements of pistons 11 in the usual manner. In addition to arm 21, shaft 20 carries an additional arm 21a, angularly spaced from arm 21 as shown. The ends of arms 21 and 21a are rotating or moving contacts cooperating with the fixed contacts 15 in the usual manner.

Arms 21 and 21a are electrically connected together and connected, through a slip ring arrangement not shown, by wire 22 to one terminal of the secondary winding of a coil or transformer 23 whose other terminal is grounded, one terminal of each plug 12 being grounded in the usual manner.

The primary of coil 23 has one terminal conventionally connected through a resistor 24 and ignition switch 25 to the positive terminal of battery 26, or other power source. The negative battery terminal is connected to ground and the other coil primary is connected in the usual manner to one contact of a timer arrangement 27, the other timer contact being connected through ground to the negative battery terminal. A capacitor 28- is con nected between the first timer contact and the negative battery terminal, that is, across the timer contacts 27a and 27b.

The timer 27 has the usual movable contact 27a and fixed contact 27b. The timer is arranged to break the coil circuit by opening contacts 27a and 27b by means of a rotating, eight-sided cam 29 mounted on -a shaft 30 synchronized with engine 10.

The arrangement of fixed contacts 15 about the distributor 16 and their respective connections to the eight cylinders of engine 10 determine that the firing order of engine 10 is cylinders l, 8, 4, 3, 6, 5, 7, 2 in the particular engine selected for FIGURE 2. Arm 21a is angularly spaced behind arm 21 degrees, as shown. Each time the timer contacts 27a and 27b are separated a high voltagepulse is induced in the secondary of coil 23 in the usual manner and a spark, or momentary sparking, occurs at whichever plug is connected to the contact 15 in connection with arm 21 at that moment. The connection of shaft 20 with motor ensures that the piston 11 of that cylinder is then at the start of its power cycle or stroke.

Arm 21a, however, is electrically connected to arm 21 and in contact with a different cylinder at that same time, with cylinder 5 when No. 1 is firing, with cylinder 7 when No. 8 is firing, and so on. Each contact is connected through a respective capacitor 17 to its respective plug 12 and this ensures that both plugs are fired alternately. Oscilloscope analysis of the coil primary circuit indicates at least two sparks at each plug, the time interval of the oscillations, measured in microseconds, being so short as to be only momentary and producing practically simultaneous firing at each plug. FIGURE 2 indicates this in that, when No. l is fired for its power stroke, No. 5 fires simultaneously for scavenging at 90 degrees of crankshaft rotation after its exhaust stroke has commenced, and when No. 8 fires for power, No. 7 fires simultaneously for scavenging, etc., as indicated in FIGURE 2.

FIGURE 3 shows another distributor 31 which, it will be understood, is connected in the ignition system of a six cylinder engine in the same manner as distributor 16 in FIGURE 1. Distributor 31 has six equiangularly spaced fixed contacts 32 and two rotating contact arms 33 and 33a, angularly spaced at 120 degrees, carried on a shaft 34 synchronized with the six cylinder engine. Each fixed contact 32 is connected through a capacitor 35, to a plug, 3

not shown, in the respective cylinder of the engine.

It will be apparent that the operation of distributor 31 for a six cylinder engine is substantially the same as that described for distributor 16 except for the firing order being that shown in FIGURE 4. When No. 1 cylinder fires for power, No. 2 fires substantially simultaneously for scavenging, and so forth. Due to spacing of contacts 32 around the distributor arm 33a is spaced from arm 33 120 degrees and when No. 2 fires for scavenging its piston is about /3 through its exhaust stroke.

In FIGURE 5 the distributor 36 is adapted for use with a four cylinder engine. There are four equiangularly spaced stationary contacts 37 and the lead wires to the respective spark plugs are each provided with a capacitor 38. Two arms 39 and 39:: are carried on the distributor shaft 40, angularly spaced at 90 degrees.

The operation of distributor 36 is likewise the same as distributor 16 except the firing order is l, 2, 4, 3 in this instance and the order of simultaneous scavenger sparking is 3, 1, 2, 4. Due to the spacing of contacts 37, when No. 3 is fired for scavenging it is at the beginning of its exhaust stroke.

-In FIGURE 6, a distributor 41 is shown having six equiangularly spaced contacts 42 with lead wires to the respective cylinders. Two angularly spaced arms 43 and 43a are carried on shaft 44 but the contact portions of arms 43 and 43a are electrically insulated from one another and from shaft 44.

Arms 43 and 43a are each electrically connected to a terminal of a respective secondary winding 45a and 45b of a coil 45. The other terminal of each secondary winding is grounded.

The primary of coil 45, which may be a single coil or two coils in series, as shown, is connected at one end to the negative grounded terminal of battery 47 and at the other end to one of a pair of contacts 48a and 48b of a timer 48. The other timer contact is connected through an ignition switch 49 to the positive terminal of battery 47. The usual capacitor 50 is connected across the timer contacts 48a and 48b.

The movable contact 48a is operated to break the circuit through the primary of coil 45 for each cylinder power stroke by the six-sided timer cam 51 carried on shaft 44 or another shaft rotating synchronously therewith.

The operation of this modified ignition system is much the same as that shown in FIGURE 1. For each power stroke the circuit through the primary of coil 45 is broken, inducing a high tension current surge in each of the secondary windings 45a and 45b which is communicated through the respective arms 43 and 43a of the distributor. When contact arm 43 is in contact with contact 42 connected to the plug at cylinder No. 1, arm 43a is in contact with fixed contact 42 connected to the plug at No. 2, so that sparks at both plugs are induced. Since each of the arms 43 and 43a are connected to a separate coil secondary there is no need for any capacitor in the lines between the fixed contacts 42 and the plugs at the cylinders.

In FIGURE 7, another modification of an ignition system adapted for the practice of the invention is shown. The distributor 56 has six equiangularly spaced fixed contacts 57, each connected to a respective cylinder plug, not shown. Two angularly spaced rotating contact arms 59 and 59a are carried on the distributor shaft 60, each arm insulated from the other and from the shaft.

Arm 59 is electrically connected to one terminal of the secondary winding 61a of a coil 61, the other terminal being grounded. Arm 59a is connected to one terminal 62a of the secondary winding of a coil 62, the other terminal being grounded. The respective primary windings of coils 61 and 62 each have one end connected to the negative grounded terminal of a battery 63 and the other end connected respectively to one contact of a pair in timers 64 and 65. Each pair of timer contacts has the other contact of the pair connected through a respective resistor 66 and through an ignition switch 67 to the positive terminal of battery 63. The usual capacitors 68 are connected across each pair of contacts.

Six sided timer cams 69 and 70 may both be mounted on distributor shaft 60, as shown, or on separate shafts synchronized with shaft 60 and the engine.

Preferably the timer cams are adjustably mounted but, in any event, they are mounted to break the circuit through their respective coil primaries at different angular positions of the timer arms 59 and 59a. For example, when arm 59 is in contact with the fixed contact 57 for No. 1 cylinder, the cam 69 breaks the circuit through the primary of coil 61, but the contact through coil 62 is not broken until arm 59a reaches the point of contact with its fixed contact 57 connected to No. 2 cylinder.

In operation, arms 59 and 59a have independent timers and independent coils so that it is possible, by adjusting cams 69 and 70, to obtain, for each power stroke, first a power sparking at that cylinder, No. 1 as shown, and, an instant later, a sparking at another cylinder, No. 2, as shown, for the scavenging sparking at that other cylinder.

FIGURE 8 illustrates this non-simultaneous timing of power and scavenge sparking. First No. 1 fires at its power stroke commencement. After an instants delay, No. 2 fires in its exhaust stroke, as shown, 15 degrees movement of the timer arms after the firing of No. 1. In the same manner, No. 4 fires in its exhaust stroke after No. 5 fires in its power stroke, and No. 1 fires in its exhaust stroke an instant after No. 3 fires for ignition in its power stroke.

It will be apparent to those expert in the art that other ignition systems, including transistorized systems, may be adapted for use in carrying out the invention. By providing spark plugs at each cylinder in diesel engines, a spark to ignite the unconsumed gases during the exhaust stroke may be obtained by timing the sparking at the plug with the movement of the piston in the cylinder.

In constructed embodiments of ignition systems according to the invention for both six and eight cylinder engines not only cleaner exhausts were obtained but also gas savings, in miles per gallon, were obtained amounting to as much as 15 to 25 percent increased mileage.

As will be apparent to those familiar with the art, the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiments disclosed therefore are to be considered in all respects as illustrative, rather than restrictive, the scope of the invention being indicated by the appended claims.

What is claimed is:

1. In an internal combustion engine having a plurality of cylinders and reciprocating pistons therein arranged to sequentially have successive intake, compression, power, and exhaust strokes; ignition means including a high tension current source, timing means for momentarily interrupting current in the high tension source, and distributor means having a first distributor arm rotating synchronously with the reciprocation of the pistons and adapted to momentarily communicate a spark to each cylinder substantially at the commencement of its power stroke; the improvement comprising the distributor means having a second arm rotating electrically connected to the first arm and secured in a fixed angular relation to the first arm for successively momentarily communicating a spark to each cylinder during the first half of its exhaust stroke; whereby unburnt gases in each cylinder are ignited to be burnt in the cylinder during its exhaust stroke.

2. An internal combustion engine having a plurality of cylinders and reciprocating pistons therein arranged to sequentially have successive intake, compression, power, and exhaust strokes; and ignition means, comprising: a source of electricity, a coil having its primary winding connected across the source, circuit breaker means synchronized with the reciprocation of the pistons for momentarily breaking the circuit through the coil primary, a single spark plug having spaced electrodes at each cylinder, a distributor having a first rotating contact electrically connected to one end of the coil secondary winding and a plurality of equi-angularly spaced fixed contacts each connected through a capacitor to one electrode of a respective plug for successively causing a momentary sparking at the plugs, the other end of the coil secondary winding and the other plug electrodes being grounded, the distributor having a second rotating contact electrically connected to the first rotating contact and angularly spaced from the first rotating contact at an angle which is a multiple of the angular spacing of the fixed contacts, whereby breaking of the circuit through the coil primary causes momentary sparking at one plug when its associated piston is substantially at the commencement of its power stroke and substantially simultaneously causes momentary sparking at another plug while its associated piston is in the first half of its exhaust stroke.

3. An internal combustion engine having a plurality of cylinders and reciprocating pistons therein arranged to sequentially have successive intake, compression, power, and exhaust strokes; and ignition means, comprising: a source of electricity, a coil having its primary winding connection across the source, circuit breaker means synchronized with the reciprocation of the pistons for momentarily breaking the circuit through the coil primary, a single spark plug having spaced electrodes at each cylinder, a distributor having a first rotating contact electrically connected to one end of one of a pair of coil secondary windings and a plurality of equi-angularly spaced fixed contacts each connected to one electrode of a respective plug for successively causing a momentary sparking at the plugs, the other end of said one coil secondary winding and the other plug electrodes being grounded, the distributor having a second rotating contact insulated from and angularly spaced from the first rotating contact at an angle which is a multiple of the angular spacing of the fixed contacts, the second rotating contact being electrically connected to one end of the other coil secondary winding, the other end of said other coil secondary winding being grounded, whereby breaking of the circuit through the coil primary causes momentary sparking at one plug when its associated piston is substantially at the commencement of its power stroke and substantially simultaneously causes momentary sparking at another plug while its associated piston is in the first half of its exhaust stroke.

4. An internal combustion engine having a plurality of cylinders and reciprocating pistons therein arranged to sequentially have intake, compression, power, and exhaust strokes; and ignition means, comprising: a source of electricity, a pair of coils each having its primary winding connected across the source, circuit breaker means associated with each coil and synchronized with the reciprocation of the pistons for momentarily breaking the circuit through the coil primary, a spark plug having spaced electrodes at each cylinder, a distributor having a first rotating contact electrically connected through one of the coil secondary windings to ground and a plurality of angularly spaced fixed contacts each connected to one electrode of a respective plug for successively causing a momentary sparking at the plugs, the other plug electrode being grounded, the distributor having a second rotating contact insulated from and angularly spaced from the first rotating contact, the second rotating contact being electrically connected through the other coil secondary winding to ground, the circuit breaker means being adjusted to break the current through one coil an instant after the circuit is broken through the other coil, whereby a momentary sparking in one cylinder occurs at the commencement of its power stroke and momentary sparking at another cylinder occurs an instant later during its exhaust stroke.

References Cited UNITED STATES PATENTS 1,580,353 4/1926 Vincent.

2,465,080 3/1949 Fitzsimmons.

3,242,916 3/1966 Coufal.

3,331,201 7/1967 Guin 30 LAURENCE M. GOODRIDGE, Primary Examiner.

US. Cl. X.R. 

